Metal-oxide semiconductor ("MOS") technology is now preferred in the manufacturing of many semiconductor devices and circuits. Complementary MOS ("CMOS") circuitry is often a preferred technology for implementation of integrated circuits because of associated small levels of power dissipation.
CMOS technology advances have been characterized by a scaling of the power supply voltage required to activate the CMOS circuitry. Various CMOS technologies require 5 volt, 3.6 volt, and 2.5 volt power supplies. A potential for "punch through" exists if too high of a voltage is applied to the thin oxide gate associated with mixed technologies. The problem arises when there is a situation where a system design utilizes a mix of these technologies thus requiring different power supply voltages. As a result of such a situation, the output signals from one technology are not directly compatible with the input signal requirements of another CMOS technology. Therefore, if the system requires that a signal be communicated from a first circuit implemented in one CMOS technology of a higher voltage than a second circuit implemented in a different CMOS technology of a lower voltage, it is likely that a significant portion of this communication will be lost, degrading or destroying the reliability of the system.
Thus, there is a need in the art for a technique to convert signal levels communicated between circuits implemented in different CMOS technologies so that the circuits are compatible.